Re: [PATCH v6 03/22] cat-file tests: test for missing object with -t and -s

On Thu, Sep 16 2021, Taylor Blau wrote:

On Tue, Sep 07, 2021 at 12:57:58PM +0200, Ævar Arnfjörð Bjarmason wrote:

quoted

Test for what happens when the -t and -s flags are asked to operate on
a missing object, this extends tests added in 3e370f9faf0 (t1006: add
tests for git cat-file --allow-unknown-type, 2015-05-03). The -t and
-s flags are the only ones that can be combined with
--allow-unknown-type, so let's test with and without that flag.

I'm a little skeptical to have tests for all four pairs of `-t` or `-s`
and "with `--allow-unknown-type` and without `--allow-unknown-type`".

Testing both the presence and absence of `--allow-unknown-type` seems
useful to me, but I'm not sure what testing `-t` and `-s` separately
buys us.

(If you really feel the need test both, I'd encourage looping like:

Thanks, I'll try to simplify it.

    for arg in -t -s
    do
      test_must_fail git cat-file $arg $missing_oid >out 2>err &&
      test_must_be_empty out &&
      test_cmp expect.err err &&

      test_must_fail git cat-file $arg --allow-unknown-type $missing_oid >out 2>err &&
      test_must_be_empty out &&
      test_cmp expect.err err
    done &&

but I would be equally or perhaps even happier to just have one of the
two tests).

A loop like that can be further simplified as just (just inlining
arg=-s):

	test_must_fail git cat-file -s $missing_oid >out 2>err &&
	test_must_be_empty out &&
	test_cmp expect.err err &&

	test_must_fail git cat-file -s --allow-unknown-type $missing_oid >out 2>err &&
	test_must_be_empty out &&
	test_cmp expect.err err

:)

I.e. unless you end &&-chains in loops in the test framework with an ||
return 1 you're only testing your last iteration. Aside from whatever
I'm doing here I generally prefer to either just spell it out twice (if
small enough), or:

    for arg in -t -s
    do
        test_expect_success '...' "[... use $arg ...]"
    done

Which both nicely get around the issue of that easy-to-make mistake.

We've got some in-tree tests that are broken this way, well, at least
4cf67869b2a (list-objects.c: don't segfault for missing cmdline objects,
2018-12-05). But I think I'll leave that for a #leftoverbits submission
given my outstanding patch queue..., oh there's another one in
t1010-mktree.sh ... :)